Ultrastiffness and metallicity of rhenium nitrides

The equation of states, mechanical properties and electronic structures of the recently synthesized rhenium nitrides (Re3N and Re2N) and the pure metal Re have been investigated by the density functional theory calculations considering the effect of spin-orbit coupling. Our results not only indicate Re3N and Re3N to be ultrastiff and hard materials but also reveal that they exhibit mechanical stability and metallic character. Furthermore, the mechanical behaviors for Re, Re3N, and Re3N can be qualitatively clarified from their crystal and electronic structures. The metallic, ultrastiff, and hard Re3N and Re2N may find their promising applications as cutting tools and hard conductors at the extreme conditions. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556450]